How to access your Rails session ID

It might sometimes be useful to check whether your Rails application accesses the file system unnecessarily, for example if your file system access is slow because it goes over the network.

The culprit might be a library like carrierwave that ch...

Note: Modern Rails has two build pipelines, the asset pipeline (or "Sprockets") and Webpacker. The principles below apply for both, but the examples shown are for Sprockets.

Every page in your application uses many assets, su...

This is a small example on how you can check if your Postgres index can be used by a specific query in you Rails application. For more complex execution plans it might still be a good idea to use the same path of proof.

1. Identify the...

This is for you when you want to mount a dmcrypt encrypted partition manually, e.g. from a live CD.

First, open the dmcrypted partition (You need to provide some name. It may, but does not need to, be your LVM group name):

cryptsetup luksO...

Unfortunately vanilla Ruby modules lack support for many idioms popular in modern Ruby. Most importantly, we have become accustomed to composing our classes with meta-programming macros such as has_many, validates_presence_of or after_save. And mo...

General

Programatically invoke Rails generators

Require the generator, instantiate it and invoke it (because generators are Thor::Groups, you need to invoke them with invoke_all). Example:

  require 'generators/wheelie/haml...

Rails gives you migrations to change your database schema with simple commands like add_column or update.
Unfortunately these commands are simply not expressive enough to handle complex cases.

...

At makandra, we've built a few gems over the years. Some of these are quite popular: spreewald (> 1M downloads), active_type (> 1M downloads), and geordi (> 200k downloads)

Developing a Ruby gem is different from developing Rails applications, w...

Expiration of Rails sessions

By default Rails sessions expire when the user closes her browser window.

To change this edit your config/initializers/session_store.rb like this:

ActionController::Base.session = ...

If another session is accessing your database you are trying to reset or drop you might have seen the following error:

PG::ObjectInUse: ERROR:  database "foo_development" is being accessed by other users
DETAIL:  There is 1 other session usi...